A subgroup analysis of data from a nationwide study (KCSG-ST19-16) was performed to evaluate the efficacy and safety of second-line ramucirumab plus paclitaxel treatment in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastro-esophageal junction (GEJ) adenocarcinoma.

The KCSG-ST19-16 study enrolled a total of 1063 patients from 56 hospitals in South Korea with advanced gastric or GEJ adenocarcinoma, who had received second-line treatment with ramucirumab plus paclitaxel. HER2 status was known for 994 (93.5%) of these patients, who were thus included in the subgroup analysis.

In total, 163 of 994 patients (16.4%), had HER2-positive gastric or GEJ adenocarcinoma. The objective response rate to ramucirumab plus paclitaxel treatment was significantly higher in patients with HER2-positive disease compared to those with HER2-negative disease (23.0% [95% confidence interval (CI), 15.9-30.1] vs. 15.1% [95% CI, 12.3-17.9], p = 0.025). The median progression-free survival was longer in patients with HER2-positive versus HER2-negative disease, but the difference was not statistically significant (4.3 months [95% CI, 3.7-5.3] vs 3.7 months [95% CI, 3.4-4.0], p = 0.054). There was no statistically significant difference in median overall survival (OS) between the groups (9.8 months [95% CI, 8.9-12.3] vs 10.1 months [95% CI, 9.2-10.9], p = 0.564).

In patients with HER2-positive gastric or GEJ adenocarcinoma, the objective response rate to second-line treatment with ramucirumab plus paclitaxel was significantly higher compared to patients with HER2-negative disease. However, an increased response to treatment was not associated with an improvement in OS.